You have specialized in manipulating a specific element to its fullest, making your spells of that element exceptionally powerful. You gain the following benefits:

• Choose one type of elemental damage: fire, cold, lightning, or acid. When you cast a spell that deals damage of that type, you can ignore resistance to that damage type. This does not affect immunities.
• Once per long rest, when you cast a spell that deals your chosen elemental damage, you can add your spellcasting modifier to the damage of the spell against one of its targets, in addition to any other bonuses.
• Spells you cast that deal your chosen elemental damage type are more difficult to resist. Add +1 to the spell save DC for such spells.
• You can convert energy from one elemental type to your chosen type once per short rest. When you cast a spell that deals elemental damage, you can change that spell's damage type to match your chosen type.

This feat exemplifies your mastery over a specific elemental type, allowing you greater versatility and potency when using spells that harness that element.